1. Field of the Invention
The present invention relates to an optical connector plug for supporting leading ends of optical fibers and an optical connector for coupling the optical fibers to each other.
2. Description of the Related Art
Conventional optical coupling between optical fibers used for optical communication has been made through a method of using an optical connector including optical connector plugs for supporting leading ends of optical fibers and an optical connector adapter for fixedly attaching optical connector plugs to each other for optical coupling of the optical fiber, or a method of welding the leading ends of the optical fibers in a state in which they come into contact with each other.
The optical coupling between optical fibers using the welding method has a problem in that the optical coupling of the optical fibers cannot be made in a detachable manner or a problem of limited use of the optical fibers due to troublesomeness of the welding process.
To overcome these problems, a SC-type optical connector for coupling optical fibers to each other using a barrel-shaped body used as a ferrule with an outer diameter of 2.5 mm for supporting the optical fibers or a relatively miniaturized MU-type optical connector using a barrel-shaped body used as a ferrule with an outer diameter of 1.25 mm for supporting the optical fibers is being employed so as to facilitate attachment and detachment of the optical coupling of the optical fibers without requiring the welding process of the optical fibers.
In addition, recently, FTTH (Fiber To The Home) for establishing high speed communication environments using access networks, which are formed by optical fibers, for connecting subscriber lines from a telephone office to homes is spreading. In this optical fiber communication, an infrared ray with a wavelength of 1.3 to 1.55 μm is commonly being used and its power tends to increase.
In addition, a cover to cover the leading ends of the optical fiber plugs is provided on the circumference of the optical connector in order to protect the leading ends of the optical fibers from contaminants, such as dusts, fingerprints, and sprays of water (for example, see Patent Document 1 and Patent Document 2).
However, in the conventional SC-type and MU-type optical connector plugs, if a human body, particularly, a part such as eyes, is exposed to light emitted from the leading ends of the supported optical fibers for more than certain time, there is a high possibility of having a bad affect on the human body.
Particularly, a high safety is required for the optical connector plugs for supporting the leading ends of the optical fibers led into households according to the spread of the FTTH to the households. However, the general SC-type or MU-type optical connector plug used for the FTTH has no measure to shield the human body from light emitted from the leading ends of the optical fibers, thereby causing a high possibility of exposure of the human body to light. In addition, there is a problem in that the increase of power in the optical communication increases a risk that light emitted from the leading ends of the optical fibers has a bad affect on the human body.
The above-mentioned conventional arts disclose the optical connector plug provided with the cover for protecting the leading ends of the optical fibers from contaminants and shielding the human body from light emitted from the leading ends of the optical fibers. However, since the cover is provided on the circumference of the optical connector plug, the optical connector plug has a modified shape different from its original shape. Also, the optical connector adaptor for coupling optical connector plugs to each other has a modified shape different from its original shape, according to the modified shape of the optical connector plug provided with the cover, thereby resulting in high product costs.
In addition, the optical connector provided with the cover must have new standard requirements different from those of the conventional SC-type and MU-type optical connectors, and accordingly, has no compatibility with the conventional SC-type and MU-type optical connectors. Accordingly, in order to make an actual application of the optical connector provided with the cover with the new standard requirements, existing equipment employing the conventional SC-type or MU-type optical connector must be replaced with anew one, which results in high product costs.
[Patent Document 1]
Japanese Patent Laid-Open No. 7-281055 (pages 4 to 6, FIGS. 1, 7 and 8)
[Patent Document 2]
Japanese Patent Laid-Open No. 2002-156557 (pages 4 to 6, FIGS. 1, 7 and 8))
In consideration of the above-mentioned problems, it is an object of the invention to provide an optical connector-plug and an optical connector, which are capable of providing high safety by shielding light emitted from optical fibers easily and reliably, and reducing product costs and introduction costs thereof.